One commenter responded by quoting Fox News’s figure: only 17% of the guns recovered in Mexico originate in the U.S. I sought the source of that statistic and found, without too much shock, that it too was wrong.

Annenburg Political Fact Check reviews the available statistics, debunks both figures, and comes up with their own. They report that in 2007-2008, ATF traced 11,055 guns captured in Mexico and found that 10,347 of them originated in the U.S. So more than 93% of the guns ATF traced originated on this side of the border.

But they didn’t trace every gun. Mexican authorities say they captured 29,000 guns over the same period, but only submitted those they thought likely to originate in the U.S. That means about 36% of the total number of guns captured originated in the U.S.

Annenberg warns that hard numbers are scarce, and this is at best a good estimate. But it does suggest (as I suspected) that people on both sides of the issue are fudging their numbers.

While we’re on statistics, ATF reports that they have analyzed weapons seizures from the U.S. and come up with the following list of weapons favored by Mexican gangsters:

As with everything else related to this issue, this report is ambiguous. My best reading is that they analyzed seizures of weapons headed for Mexico, and that this list is in order of volume. (It’s not listed by order of caliber, size, or name.) If true, it suggests that 9mm, .38 Super, and .45 pistols are far more popular than assault rifles. That again is my best guess. But it is clear there are an awful lot of ordinary (non-tactical) pistols heading for Mexico.

Is ten thousand weapons from the U.S. in two years too many? Of course it is, and I support efforts to reduce the smuggling of weapons across the border. (ATF offers this helpful list of the characteristics of a likely smuggler.)

But take note: The most numerous weapons being smuggled are the same common pistols homeowners use for self-defense– nothing special. And 2/3 of the weapons captured in Mexico came from somewhere other than the U.S. If we think we can stop the border violence by banning assault weapons here– or even all guns– we’re fooling ourselves.